Portland Association

Portland Cement, , Volume 18/Number 2 and Heat of Hydration July 1997 When is mixed Fig.1 demonstrates the effect of 5420 Old Orchard Road with water, heat is liberated. This element size on concrete tempera- heat is called the heat of hydration, ture with time due to the heat of Skokie, Illinois 60077-1083 the result of the exothermic chemical hydration. reaction between cement and water. Temperature rises of 55°C (100°F) Phone: (847) 966-6200 The heat generated by the cement’s have been observed with high ce- hydration raises the temperature of ment content mixes.(2) These tem- Fax: (847) 966-8389 concrete. perature rises cause expansion while Web Site: www.portcement.org During normal concrete construc- the concrete is hardening. If the tem- tion, the heat is dissipated into the perature rise is significantly high soil or the air and resulting tempera- and the concrete undergoes nonuni- Contents ture changes within the structure are form or rapid cooling, stresses due not significant. However, in some to thermal contraction in conjunction situations, particularly in massive with structural restraint can result in Portland Cement, Concrete, structures, such as , mat foun- cracking before or after the concrete and the Heat of Hydration dations, or any element more than eventually cools to the surrounding about a meter or yard thick, the heat temperature. Contractors often insu- Cement on the Go can not be readily released. The late massive elements to control tem- mass concrete may then attain high perature changes. As a rule of internal temperatures, especially thumb, the maximum temperature during hot weather construction, or differential between the interior and if high cement contents are used. exterior concrete should not exceed

50 Cement content 360 kg/m3 (605 lb/yd3) 40 , 18-mm-thick plywood (0.71 in) 110 Temperature taken at center of wall F C ° ° ° ° Ambient temperature, 5 C (41 F) 30 * Wall thickness, mm (in.) 90

1000 (40)* 70 20 300 (12) 500 (20) 700 (27.5) Continuing Studies of Temperature, Temperature, Concrete in Sulfate Soils 10 50

Reinforcement News 0 32 02468101214 New Literature Time (days)

Fig. 1. Effect of member thickness on temperature of concrete. Reference 1.

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120 20°C (36°F) to avoid crack develop- types (average = 88.5 cal/g at 7 days) B B (3) B ment. The potential for thermal and Type IV has the lowest (average = B 100 cracking is dependent on the 55.7 cal/g at 7 days). B concrete’s tensile strength, coeffi- Portland cement evolves heat for a 80 B cient of thermal expansion, tempera- long time.(4) Reference 4 and Fig. 2 ture difference within the concrete, present heat of hydration data out to 60 B and restraint on the member. 13 years. Fig. 2 shows that the rate of Concrete placed in cold conditions heat generation is greatest at early 40 Type I cement benefits from the heat generated by ages. Usually, the greatest rate of heat W/C = 0.40 cement hydration, helping protect it liberation occurs within the first 24 Heat of hydration, cal/g 20 Cured at 21°C (70°F) from freezing and providing a more hours and a large amount of heat favorable curing temperature. Adding evolves within the first 3 days. For 0 insulation to the formwork helps trap most concrete elements, such as pave- 1 10 100 1000 10000 the heat in the concrete, allowing it to ments, long-term heat generation is Time, days (log scale) achieve the required strength. not a concern as this heat is dissipated Fig. 2. Average heat of into the environment. hydration of a Type I cement at Heat of Hydration of various ages to 13 years. Portland Factors Affecting Reference 4. Heat of Hydration The heat of hydration of cement is heat, and at a faster rate, than usually determined in accordance Materials can be selected to minimize dicalcium silicate or other cement with ASTM C 186, Standard Test or maximize the heat of hydration, de- compounds. Sulfate content, in its Method for Heat of Hydration of Hy- pending on the need. Cements with relation to controlling the hydra- draulic Cement (see box). Table 1 has higher contents of tricalcium silicate tion of calcium aluminate, partici- heat of hydration values for a vari- and tricalcium aluminate, as well as a pates in the rate of heat liberation. ety of portland cements from 1992 to higher fineness, such as Type III ce- Higher fineness provides a 1996. Although this data is very lim- ments, have higher rates of heat gen- greater surface area to be wetted, ited, it confirms the general trends eration than other cements. resulting in an acceleration of the expected: Type III cement has higher Tricalcium silicate and tricalcium reaction between cement and wa- heat of hydration than other cement aluminate chemically generate more ter. This causes an increase in the

Table 1. ASTM C 186 Heat of hydration for selected portland cements, calories per gram* Type I cement Type II cement Type II Type III cement Type IV cement Type V (moderate cement heat) cement No. 7 day 28 day No. 7 day 28 day No. 7 day No. 7 day 28 day No. 7 day 28 day No. 7 day 1 82.0 —** 16 77.7 101.4 32 67.6 36 88.0 99.0 38 60.0 — 41 81.5 2 85.6 — 17 82.6 88.8 33 65.0 37 89.0 95.0 39 57.3 — 42 66.5 3 81.6 — 18 88.7 89.4 34 54.3 40 49.7 65.5 43 79.3 4 80.2 — 19 88.0 — 35 64.7 44 80.4 5 78.4 — 20 73.6 — 45 76.1 6 88.3 90.2 21 88.5 — 46 61.4 7 88.2 106.1 22 77.1 89.7 8 87.7 93.5 23 87.3 — 9 88.9 97.7 24 81.9 100.3 10 76.4 91.7 25 88.3 99.4 11 84.4 91.7 26 86.5 96.8 12 84.4 98.5 27 79.5 — 13 83.5 — 28 79.4 — 14 79.5 — 29 80.0 — 15 83.0 — 30 80.0 — 31 77.6 —

Avg. 83.5 95.6 Avg. 82.3 95.1 Avg. 62.962.9 Avg. 88.588.597.0 97.0 Avg. 55.7 65.5NM Avg. 74.274.2 Max. 88.9 106.1 Max. 88.7 101.4 Max. 54.367.6 Max. NM89.0NM 99.0 Max. 49.760.0 65.5NM Max. 81.581.5 Min. 76.4 90.2 Min. 73.6 88.8 Min. 67.654.3 Min. NM88.0NM 95.0 Min. 60.049.7 65.5NM Min. 61.461.4 % of % of Type* This I table is based on limited data provided by various testing laboratories and cement companies. The cements were Typetested I between100 1992 and 1996. 99 75 106 67 89 (7 day ** No data available. (7day)avg.) NM: not meaningful. 1 cal/g = 4.184 kJ/kg

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Tests for Heat of Hydration dry cement heat of solution and the ture (for example, by a thermo- Two methods of determining the heat capacity of the container, the electric device). Water is added heat of hydration are commonly heat of hydration for the desired hy- and the energy required to main- used. ASTM C 186, Standard Test drating period can be calculated. tain the sample temperature is Method for Heat of Hydration of Hy- Samples can be hydrated any length continuously recorded. By integra- draulic Cement, uses a heat of solu- of time with this technique. tion, the heat of hydration at any tion procedure. In this test, a The other common method is con- time can be obtained; however, sample is dissolved in an acid so- duction calorimetry. In this non- the length of the test is usually lution inside a well-insulated con- standard procedure, a sample of ce- limited to 3 days as the rate of tainer and the temperature rise is ment is placed in a conductive con- heat evolution becomes too low to recorded. After correction for the tainer and kept at a specific tempera- measure beyond that time period. rate of heat liberation at early ages, tures that retard hydration delay should be specified, but not both. but may not influence the total heat development. Mineral admix- ASTM C 595, Standard Specification amount of heat developed over sev- tures, such as , can signifi- for Blended Hydraulic Cements, and eral weeks. cantly reduce the rate and amount of ASTM C 1157, Standard Performance Other factors influencing heat de- heat development. Specification for Blended Hydraulic Ce- velopment in concrete include the ment, both provide the option of cement content, water-cement ratio, Specifications for specifying moderate- and low-heat placing and curing temperature, the Reduced Heat Cements of hydration cements using physical presence of mineral and chemical limits. For moderate heat of hydra- admixtures, and the dimensions of When heat generation must be mini- tion, C 595 adds the suffix MH to the the structural element. mized in concrete, one way to cement type, calling out limits of 70 In general, higher cement contents achieve this is to choose a lower heat calories per gram (290 kJ/kg) at 7 result in more heat development. ACI cement, such as a Type II cement days and 80 calories per gram (330 211.1, Standard Practice for Selecting with the optional moderate heat of kJ/kg) at 28 days, while C 1157 (ce- Proportions for Normal, Heavyweight, hydration requirements. Not all ment Type MH) has limits of 70 calo- and Mass Concrete, states that as a Type II cements are made for a mod- ries per gram (290 kJ/kg) at 7 days rough guide, hydration of cement will erate level of heat development, as the only requirement. For low generate a concrete temperature rise however, so the moderate heat op- heat of hydration, both C 595 (LH of about 4.7°C to 7.0°C per 50 kg of tion must be specifically required suffix) and C 1157 (Type LH ) have cement per m3 of concrete (10°F to (see Table 1). Type IV, low heat of limits of 60 calories per gram (250 15°F per 100 lb of cement per yd3 of hydration cement, can also be used kJ/kg) at 7 days and 70 calories per concrete) in 18 to 72 hours. to control temperature rise, but it is gram (290 kJ/kg) at 28 days. When comparing of equal rarely available. cement content but different water- ASTM C 150, Standard Specification Controlling Concrete cement ratios, mixes with higher for Portland Cement, allows two inde- Temperature Rise water-cement ratios have more water pendent approaches to control heat and microstructural space available of hydration in cement. The first The temperature rise of concrete can for hydration of the cement (more of method is to specify chemical re- be controlled by selecting appropri- the cement hydrates and it hydrates at quirements. For Type II cement, an ate materials and construction prac- a faster rate), resulting in an increased optional limit on the sum of the tices. For cold weather, ACI 306R, rate of heat development. The increase tricalcium silicate (C3S) and Cold Weather Concreting, recom- in heat of hydration at 7 days result- tricalcium aluminate (C3A) contents mends minimum mixing and plac- ing from an increase in water-cement is set at 58%. For Type IV cement, ing temperatures based on the size ratio from 0.4 to 0.6 is about 11% for limits are placed on the C3S and C3A of the concrete member and the am- Type I cement. The effect is minimal contents at a maximum of 35% and bient air temperature. (As tempera- for moderate- and low-heat cements.(4) 7%, respectively, while maintaining tures and member thickness de- crease, conditions become more criti- The water-cement ratio effect is minor a minimum dicalcium silicate (C2S) compared to the effect of cement con- content of 40%. The second method cal.) ACI 306R offers guidance on in- tent. However, a lower water-cement uses physical requirements. For creasing the temperature of fresh ratio in concrete achieved by increas- Type II cement, the optional maxi- concrete, including heating aggre- ing the cement content results in mum heat of hydration is 70 calories gates and mixing water. Other op- greater heat generation. per gram (290 kJ/kg) at 7 days. For tions include reducing the length of Higher temperatures greatly accel- Type IV cement, the maximum heat the required protection period by us- erate the rate of hydration and the of hydration is limited to 60 calories ing Type III cement, by using an ac- rate of heat liberation at early ages per gram (250 kJ/kg) at 7 days and celerating admixture, or by using an (less than 7 days). Chemical admix- 70 calories per gram (290 kJ/kg) at extra 60 kg/m3 (100 lb/yd3) of ce- tures that accelerate hydration also 28 days. Either the chemical ap- ment. Also, insulation could be used accelerate heat liberation and admix- proach or the physical approach to trap the heat in the fresh concrete,

3 Return To Index Concrete Technology Today thereby protecting it. 100 For massive structures, or to con- 50 Cube center Type I cement: 564 kg/m3 (950 lb/yd3) trol temperature rise in hot weather, Insulation added at 2.3 hours ACI 305R, Hot Weather Concreting, Insulation removed at 73 hours 80 Form removed at 118 hours recommends controlling mixing and 40 Laboratory air temp 17-20°C (62-68°F) F C ° placing procedures to minimize de- ° lays and to use the cooler parts of the 60 day for placing operations. There are 30 Near surface numerous methods to minimize the concrete temperature rise. These in- 40 clude cooling the mixing water, us- 20 Temperature rise, Temperature ing ice as part of the mixing water, rise, Temperature using a moderate-heat Type II 10 20 (ASTM C 150) portland cement or moderate- or low-heat blended ce- ment (ASTM C 595 or C 1157), and 0 0 keeping cement contents to a mini- 0 20 4060 80 100 120 140 160 180 mum level. A fly ash or other poz- Time after batching, hours zolan or slag can be used, chemical admixtures (retarder, water-re- Fig. 3. Temperature rise of a high-cement-content 1.2-meter (4-ft) test ducer/retarder) can be used, or the cube. Reference 2. aggregate can be cooled. Also, water curing controls temperature in- creases better than other curing Rise in Concrete, CRD C 38, is a pro- 3. FitzGibbon, Michael E., “Large Pours methods. Reference 1 discusses the cedure to evaluate preconstruction for Structures,” Current Practice Sheets No. 28, 35, and effect of formwork material on tem- mixes for heat development. 36, Concrete, Cement and Concrete As- perature rise. Steel formwork retains References sociation, Wexham Springs, Slough, En- the least heat. gland, March and December 1976 and A proposed concrete mixture can 1. Harrison, T. A., Early-Age Thermal Crack February 1977. be tested for temperature rise in a Control in Concrete, Report 91, Construc- mock-up sample in a laboratory or tion Industry Research and Information 4. Copeland, L. E., Kantro, D. L., and the field. Fig. 3 presents results from Association, London, 1981. Verbeck, George, Chemistry of Hydration such a mock-up, showing how the of Portland Cement, RX153, Portland Ce- temperature rise differs between the 2. Burg, R. G., and Ost, B. W., Engineering ment Association, Skokie, Illinois, 1960. interior and exterior of a massive Properties of Commercially Available High- member for a high-cement-content Strength Concrete (Including Three-Year mixture. The Army Corps of Engi- Data), RD104, Portland Cement Asso- neers’ Test Method for Temperature ciation, Skokie, Illinois, 1994.

Cement on the Go Researchers of MAETA Techno-Research, Inc., a sub- sidiary of MAETA Concrete Indus- try Ltd., Yamagata, Japan have de- veloped a car body made of an ad- forced cement vanced cement-based material for a polymer-com- solar-powered car. The body mea- posite, Macro- sures 3.6 x 0.7 x 0.9 m (11.8 x 2.3 x 3.0 Defect-Free ce- ft). The molded panels have a thick- ment, formu- ness of 2.5 mm (0.1 in.) and a total lated with calcium weight of 33 kg (73 lb). The solar- aluminate cement and a phenol resin powered car ran in the 500 km precursor. The green body is made World Solar Car Rally in Akita, aver- without water, but generates water Techno-Research, aging 45 km/h (27 mph). The trial during the heating process that ini- Inc. are now working run was made to study the feasibil- tiates cross-linking of the phenol on further developments of applica- ity of utilizing cements in the trans- resin precursor. The material was in- tions in the transportation industry. portation industry. The car received vented by a research group of The car was exhibited at the the “Hans Tholstrup” award for its MAETA Concrete Industry Ltd. in MAETA Workshop on High Flex- outstanding achievement as an 1992, and patent applications have ural Polymer-Cement Composite, earth-friendly, low-energy material been granted in the United States held October 3-4, 1996 in Sakata, body. The material is a fiber rein- and Europe. Researchers of MAETA Japan.

4 Return To Index July 1997 CONTINUING STUDIES OF

CONCRETE IN SULFATE SOILS Sacramento Sulfate-Soils by David Stark, Construction Technology Laboratories, Inc. Test Facility For 57 years, the Portland Cement As the design and fabrication of con- Claire, Wisconsin, was selected to Association and Caltrans have crete evolve, new methods develop avoid possible surface popouts of maintained a test facility in Sac- to protect concrete exposed to sul- the type previously observed with ramento, California, continually fates. In order to evaluate new mate- the Elgin coarse aggregate. The third evaluating means to improve the rials, new concrete mixtures were source of coarse aggregate (Mix 53) performance of portland cement added to the PCA/CALTRANS sul- was a crushed dolomite rock from concrete embedded in sulfate- fate soils test facility in California Thornton, Illinois, and also has an bearing soils. Periodically, dete- (see box) in 1989. Results of these excellent service record. This rock tests, applied properly, can make has no history of popouts. riorated concrete specimens were concrete more durable in sulfate ex- replaced with those made from posures. Test variables and 7-year Cement. A single ASTM Type II other mixtures to evaluate newer results are described in this report. portland cement (alkali content of mixtures and materials. (Refer- ences 1 through 4). Variables 0.52% Na2O equivalent) was used Test Variables for all mixtures. Various cement fac- from the studies included cement tors were used in the mixtures. Cal- content, air content, cement fine- Ten concrete mixtures were added culated compound composition was ness, cement type, cement to the test facility and are listed in as follows: tricalcium aluminate (C3A) con- Table 1. Variables include coarse ag- tent, effects of slag, fly ash and gregate (three sources), , calcined shale, steam curing, and C3S - 53% C3A - 7% high range water reducer (HRWR), coatings of epoxy and linseed oil. C2S - 22% C4AF - 9% curing, and surface treatment. Sev- Certain general findings have eral minor mix adjustments also Silica Fume. Silica fume was used been developed in this program: were made to permit workability at a dosage of 8% by mass of and form placement. cementitious material in two of the • Reduction in the ratio of water Aggregates. Three sources of coarse test mixtures (Nos. 54 and 55) to re- to cementitious materials ap- aggregate were included in the pro- duce concrete permeability, thus pears to be the most effective gram because visual inspections of minimizing possible deterioration means of improving the per- specimens in earlier studies indi- due to sulfate attack. formance of concrete in a sul- cated that wetting and drying of the fate exposure condition, re- High-Range Water Reducer. A Na2SO4 solutions appeared to have gardless of cement type or resulted in numerous coarse aggre- high-range water reducer was used composition. gate popouts. For this purpose, the in Mix 54 (with 8% silica fume) and usual standard coarse aggregate Mix 57 (without silica fume). • Wetting and drying of concrete from Elgin, Illinois, with a maximum in sulfate-bearing solution, particle size of 25 mm (1 in.) was Surface Treatment. Two mixtures compared to continuous im- used for eight of the ten mixtures were used for sealer applications af- mersion in the solution, pro- (Nos. 51 and 54 to 60). The second ter 28 days of moist curing followed vides the most severe exposure coarse aggregate (Mix 52), from Eau by 7 days of air drying at 50% rela- condition for sulfate attack. tive humidity and 23˚C (73˚F). • ASTM type of portland ce- ment has been of less signifi- Fabrication of cance for sulfate resistance Concrete when low or high water- cementitous materials (w/cm) All but two con- ratios are used. Cement com- cretes were mixed position, particularly C A con- with sufficient water 3 to provide a 0.52 tent, is of greater importance w/cm. All concretes for sulfate performance when were non-air-en- intermediate (0.45 to 0.55) w/ trained (air contents cm are used, with lower C3A ranged from 1.0 to content as found in Type II 2.1 percent). and V cements resulting in im- After mixing, the proved sulfate resistance. concrete was placed Fig. 1. Concrete beams after 7 years in sulfate- into forms and vi- rich soil in Sacramento test facility.(# S66900) brated, spaded, fin-

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Table 1. Concrete Variables for Test Mixtures

Cement content, MineralSilica admixture, fume, Chemical Slump, Moist cure, Mix no. kg/mkg/m3 (lbs/cu3 (lb/yd 3yd)) w/cm Coarse aggregate percentkg/m3 of(lb/yd cement3) admixture mm (in.) days Sealer 51 307 0.52 Dolomitic- None None 85 28 None (517) siliceous gravel (Elgin) (3.4) 52 307 0.52 Siliceous gravel None None 95 28 None (517) (Eau Clare) (3.7) 53 307 0.52 Crushed dolomite None None 25 28 None (517) (Thornton) (1.0) 54 282 0.52 Dolomitic- 8% 24silica (41) fume HRWR 115 28 None (476) siliceous gravel (Elgin) (4.6) 55 205 0.56 Dolomitic- 8% 18silica (31) fume None 175 28 None (345) siliceous gravel (Elgin) (6.9) 56 307 0.52 Dolomitic- None None 90 7 None (517) siliceous gravel (Elgin) (3.5) 57 307 0.48 Dolomitic- None HRWR 90 28 None (517) siliceous gravel (Elgin) (3.6) 58 307 0.52 Dolomitic- None None 90 28 Silane (517) siliceous gravel (Elgin) (3.6) 59 307 0.52 Dolomitic- None None 150 28 None (517) siliceous gravel (Elgin) (6.0)

60 307 0.52 Dolomitic- None None 95 28 Siloxane (517) siliceous gravel (Elgin) (3.7)

ished with a wood float, and cov- the sulfate soils test facility; Fig. 1 mance. As in all previous studies,(1) ered with damp burlap and polyeth- shows them as they appeared 7 numerical ratings from 1.0 to 5.0 are ylene sheeting. After removal from years later. For the test exposure, tabulated. For example, a rating of the forms the day after casting, all each beam was embedded horizon- 1.0 indicates the sharp fresh appear- mixes but one were transferred to tally half-depth 75 mm (3 in.) in pre- ance of the top finished surface, cor- moist curing at 23˚C (73˚F) until 28 pared soil containing sodium sulfate ner and edges, with solid definition days of age. Concrete specimens for (Na2SO4) at a dosage of 65,000 ppm of original formed surfaces. A rating Mix 56 were moist-cured only for 7 SO4, leaving the top finished sur- of 5.0 would represent severe loss of days. After moist curing, all speci- faces of the concrete beams slightly cement paste and mortar on finished mens were transferred to air drying above the soil. The bottom of the ba- and formed surfaces, edges and cor- at 50% RH for a minimum of 28 days. sin facility was lined to minimize ners, and loss of coarse aggregate Concrete beams for two of the leakage and loss of solution during particles. Intermediate ratings repre- mixtures, Nos. 58 and 60, were storage. After totally flooding the ba- sent performance between these ex- treated with sealers. After the 28-day sin, atmospheric drying allowed the tremes (see Fig. 2). moist curing period, these concretes solution level to drop to soil level, Program Results were air-dried for 7 days at 50% RH thus permitting precipitation from and 23˚C (73˚F). For Mix 58, one ap- the saturated sulfate solution, at which point, the basin was again Seven-year results for these test plication of a water-based flooded as before. Thus, the beams beams are shown in Table 2. At each alkylalkoxysilane was brush-applied are air-dried to the top surface of the evaluation, the ponding sulfate solu- at the recommended rate of 3.7 sq m soil, then reimmersed in the desired tion was drained to better expose per liter (150 sq ft per gal), and for sulfate concentration. Roughly 10 to each beam. After seven years, all of Mix 60, a proprietary blend of silane, 15 such cycles per year were antici- these beams displayed some deterio- siloxanes, stearates, and aluminum pated, depending on atmospheric ration. However, degrees of distress compounds in a blended solvent drying and periodic precipitation. In varied, as follows. also was brush-applied in one appli- the upper portion, sulfate salts pre- • All beams ranged from generally cation, but at a recommended rate of cipitated out on the beams during minor to severe deterioration, de- 3.1 sq m per liter (125 sq ft per gal). drying while the bottom portion re- pending on mixture variables. In All test beams were then shipped to mained continuously in the highly all cases, each of three companion Sacramento for placement in the concentrated solution (in the soil). storage facility. beams for a given mixture show Performance Evaluation similar performance. Exposure Conditions at the Test Facility All concrete beams in the sulfate • The least deterioration was ob- soils facility are visually inspected served for mixtures treated with In 1989, all prisms were installed in once each year for durability perfor- sealers (Nos. 58 and 60). Ratings

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Table 2. Visual Ratings of Concrete Beams in Sulfate Soils Mix Cement content w/cm Coarse aggregate Moist curing, Admixture or Strength, 28 days Visual rating at 1,3,5,7 years* no. kg/m3(lb/yd3) days sealer MPa (psi) 1357 51 307 0.52 Siliceous dolomitic 28 None 43.1 (6250) 1.0 1.5 2.4 4.2 (517) gravel 52 307 0.52 Siliceous gravel 28 None 42.8 (6210) 1.0 1.2 3.7 3.7 (517) 53 307 0.52 Crushed dolomite 28 None 40.0 (5795) 1.0 1.4 2.5 3.5 (517) 54 282 0.52 Siliceous dolomitic 28 Silica fume + 46.9 (6795) 1.0 1.4 3.7 4.0 (476) gravel HRWR 55 205 0.56 Siliceous dolomitic 28 Silica fume 37.8 (5485) 1.3 2.4 4.2 4.3 (334.5) gravel 56 307 0.52 Siliceous dolomitic 7 None 28.0 (4064) 1.0 1.4 2.6 3.2 (517) gravel 57 307 0.48 Siliceous dolomitic 28 HRWR 48.2 (6990) 1.0 1.3 2.4 2.9 (517) gravel 58 307 0.52 Siliceous dolomitic 28 Silane 37.5 (5440) 1.1 1.0 1.3 1.3 (517) gravel 59 307 0.52 Siliceous dolomitic 28 None 37.1 (5380) 1.0 1.7 2.3 3.0 (517) gravel 60 307 0.52 Siliceous dolomitic 28 Siloxane 34.5 (5010) 1.1 1.1 1.3 1.7 (517) gravel *A rating of 1 is no deterioration and a rating of 5 is severe deterioration. Each rating is the average of three companion beams, each of which are rated by two or three observers.

posed to continuous immersion in sponsible for the facts and accuracy the laboratory. This needs further of the data presented. The contents study. do not necessarily reflect the views of the Portland Cement Association. • Type of coarse aggregate had only a minor but variable effect on sul- References fate resistance. Beams with the crushed dolomite aggregate and 1. McMillan, R. R., Stanton, T. E., Tyler, the mixture with plain siliceous I. L., and Hansen, W. C., “Concrete gravel, Mixes 53 and 52, resulted Exposed to Sulfate Soils,” Chapter 5 in in less deterioration than mixtures Long-Time Study of Cement Performance with the standard siliceous dolo- in Concrete, ACI Special Publication, Fig. 2. Illustration of durability mitic gravel. December 1949. Reprinted as Port- range corresponding (l. to r.) to land Cement Association Bulletin numerical rating of 1.1, 2.5, and • A minor reduction in w/cm, us- RX030, 1949. 5.0, respectively. (#A2885) ing HRWR to maintain workabil- 2. Verbeck, G. J., “Field and Laboratory ity, appears to have a small ben- Studies of the Sulfate Resistance of eficial effect on performance in Concrete,” Performance of Concrete. A these tests (Mix 51 versus Mix 57). Symposium in Honor of Thorbergur were 1.3 and 1.7, respectively, for Thorvaldson, ACI and National Re- the silane- and siloxane-based To date, the current rates of dete- search Council of Canada, 1968. Re- coatings. rioration of test beams due to sulfate printed as Portland Cement Associa- attack range from minor to severe. tion Bulletin RX227. • Three mixtures, Nos. 51, 54, and 3. Stark, David, “Longtime Study of 55, revealed the greatest deteriora- Acknowledgments tion. These reached ratings of 4.2, Concrete Durability in Soils,” George 4.0, and 4.3, and were, respec- The research reported in this paper Verbeck Symposium on Sulfate Resistance tively, the control mixture and the (PCA R&D Serial No. 2122) was con- of Concrete, ACI SP-77, 1982. Reprinted two mixtures with silica fume. ducted by Construction Technology as Portland Cement Association Bulle- These results may differ from Laboratories, Inc. with the sponsor- tin RD086. those of other researchers due to ship of the Portland Cement Asso- 4. Stark, David, Durability of Concrete in the difference in exposure condi- ciation (PCA Project Index No. 80– Sulfate-Rich Soils, Portland Cement tions: alternate wetting and drying 01). The contents of this paper reflect Association, RD097, 1989. in outdoor soils exposure as op- the views of the author, who is re-

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Reinforcement News bars. Contact CRSI for further infor- a week). In Canada please direct re- mation on the new soft-metric prod- quests to the nearest regional office Soft-Metricated ucts: tel. 847-517-1200; fax 847-517- of the Canadian Portland Cement 1206; e-mail [email protected]. Association (Halifax, Montreal, During 1995 and 1996, the Concrete Toronto, and Vancouver). Reinforcing Steel Institute (CRSI) Metric Inch-pound worked with ASTM, the American bar designation bar designation Association of State Highway and Proceedings of the 10th Transportation Officials, (AASHTO), #10 #3 International Congress on the and numerous U.S. state depart- #13 #4 Chemistry of Cement, LT223 #16 #5 ments of transportation to achieve This hard-cover compilation of the #19 #6 the adoption of soft-metricated rein- June 2-6, 1997 conference held in #22 #7 forcing steel as the metric standard Göteborg, Sweden is a four-volume #25 #8 for rebar usage in the United States. set comprising about 2200 pages. #29 #9 As a result, specifications for soft- Four main themes are covered: Clin- metric rebar are now available from #32 #10 ker and Cement Production; Cement ASTM (A615/A615M and A706/ #36 #11 Hydration; Additives, Admixtures, A706M) and AASHTO (M31). CRSI #43 #14 Characterisation Techniques; and is developing soft-metric design and #57 #18 Performance and Durability of construction aids for contractors, en- Cementitious Materials. Users will gineers, architects, and others. find information easily by either the CRSI rebar producers are now of- New Literature author or keyword index for the en- fering the new soft metric bars. The following publication is now tire Proceedings. Of particular inter- These bars are the same size as exist- available. To purchase it, in the est is the theme addressing perfor- ing inch-pound bars (see table for United States, contact Portland Ce- mance and durability. This state-of- designations). The number designa- ment Association, Order Processing, the-art information from around the tion indicates the nominal diameter P. O. Box 726, Skokie, IL 60076-0726; world covers ettringite, alkali-aggre- in mm for the metric bars, and in telephone 1-800/868-6733, or fax gate reaction, and deicer scaling/ eighths of an inch for inch-pound 847/966-9666 (24 hours a day, 7 days freeze-thaw resistance. This publication is intended SOLELY for use by PROFESSIONAL PERSONNEL who are competent to evaluate the sig- nificance and limitations of the information provided herein, and who will accept total responsibility for the application of this information. The Portland Cement Association DISCLAIMS any and all RESPONSIBILITY and LIABILITY for the accuracy of and the application of the information contained in this publication to the full extent permitted by law. PUBLISHER'S NOTE: Our purpose is to show various ways Direct all correspondence to of using concrete technology to your Steve Kosmatka, Editor Intended for decision makers associ- advantage and avoiding problems. If Jamie Farny, Assistant Editor ated with design, management, and there are problems or ideas readers Concrete Technology Today construction of building projects, would like discussed in future issues, Portland Cement Association Concrete Technology Today is published please let us know. Items from this 5420 Old Orchard Road triannually by the Construction Infor- newsletter may be reprinted in other Skokie, Illinois 60077-1083 mation Services Department of the publications subject to prior permis- Phone: 847/966-6200 Fax: 847/966-8389 Portland Cement Association. sion from the Association. E-mail: [email protected] E-mail: [email protected]

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